This invention relates in general to an optical switch. More specifically, the invention relates to an optical switch which has two inputs and two outputs.
In fiber optic communications and other optical applications, optical switches are used to selectively reroute signals. There have been many devices which function as optical switches. However, in order to apply those devices in harsh environments, there is a strong need in the art for an optical switch which functions with operational stability and mechanical durability. In addition, there is a need in the art for an optical switch which is compact in size and easy to manufacture.
The present invention is directed to an optical switch which includes a first set of one or more input optical fibers which send a light beam; a second set of one or more output optical fibers which receive the light beam; a lens which focuses the light beam; a movable mirror which reflects the light beam from the first set onto the second set of output optical fibers; and an actuator operative to move the mirror. The actuator selectively sets the mirror to a first position corresponding to a first combination of optical paths, through which the light beam travels from the first set to the second set, and to a second position corresponding to a second combination of optical paths, through which the light beam travels from the first set to the second set. According to the present invention, the first combination is different from the second combination, and a number of optical fibers of the first set and the second set is more than two.
In one embodiment of the present invention, the optical switch includes a ferrule which supports the first set and the second set; a package encasing the mirror and the actuator; and a window which is made of transparent material and provided on the package. The lens is a gradient index lens, and is sandwiched by the ferrule and the window.
In another embodiment of the present invention, the number of optical fibers of the second set is two.
In another embodiment, loss between the first set and the second set when the mirror is in a first position is different from loss between the first set and the second set when the mirror is in a second position.
In another embodiment, the first set has a first input optical fiber and a second input optical fiber, and the second set has a first output optical fiber and a second output optical fiber; and the first combination includes a first optical path between the first input optical fiber and the first output optical fiber, and a second optical path between the second input optical fiber and the second output optical fiber, and the second combination includes a third optical path between the first input optical fiber and the second output optical fiber, and the second input optical fiber is decoupled from the first and second output optical fibers.
In another embodiment, the first set has a first input optical fiber and a second input optical fiber, and the second set has a first output optical fiber and a second output optical fiber; and the first combination includes a first optical path between the first input optical fiber and the first output optical fiber, and a second optical path between the second input optical fiber and the second output optical fiber, and the second combination includes a third optical path between the first input optical fiber and the second output optical fiber, and a fourth optical path between the second input optical fiber and the first output optical fiber.
In another embodiment, the actuator moves the mirror by electrostatic force.
In another embodiment, the mirror and the actuator are provided on a silicon wafer.
In another embodiment, the actuator includes a plurality of interdigitated fingers.
In another embodiment, a direction of the electrostatic force is normal to a plane of the silicon wafer.
In another embodiment, the optical switch further includes a ferrule which supports the first set and the second set.
In another embodiment, the optical switch further includes a package encasing the mirror and the actuator.
In another embodiment, the package has a window which is made of transparent material.
In another embodiment, the lens is a gradient index lens, and is connected to the ferrule, and is attached to the window.